• We’re currently investigating an issue related to the forum theme and styling that is impacting page layout and visual formatting. The problem has been identified, and we are actively working on a resolution. There is no impact to user data or functionality, this is strictly a front-end display issue. We’ll post an update once the fix has been deployed. Thanks for your patience while we get this sorted.

Meaning of peak temperatures on different Q6600 cores

AigoMorla, in some recent thread, seemed to speak with authority about the placement of the four cores in a C2-Quad processor. I think he said that the cores followed this pattern:

0 1
2 3

Suppose CoreTemp reports temperatures for Cores 0 through 3 in this order:

57, 51, 55, 52

Sampling these temperatures over a one or two-hour double-ORTHOS "SMall FFTs," we find that there is little variation for each core. In other words, there are pairs of adjacent spikes for each core in the frequency distribution of temperatures, and the low-frequency values between the temperatures for the spikes are far and few between -- almost "outliers" for any given core. That is, looking at the log-file of sampled temperature readings, one would almost think that 57 was a rock-solid and unvarying temperature for core 0, etc.

The deviations between the cores seem significant and suggestive of a pattern: 57 varies from 51 by 6C-degrees; 55 varies from 52 by 3C degrees.

In speculating about a possible cause, I remembered how difficult it was to spread IC Diamond thermal paste; how I used it so sparingly that you could almost see the heat-spreader cap through the paste in certain places. So I imagine a possibility that the thermal paste layer is insufficient or unevenly spread, or that there are air-pocket irregularities in the thermal-paste layer.

Another possibility is "processor affinity" of various services running under the OS, or rather that some processes are more processor-intensive than others, and that the software design simply causes those processes to grab certain cores during system boot to Windows.

Yet another possibility is a variation in temperature sensor calibration or accuracy among the cores. Keep in mind that some of my speculations may not be fully informed, but I imagine that they are possibilities.

Are there any useful insights into this phenomenon? I may soon take a convenient opportunity to remove the heatsink, apply new TIM and reinstall the heatsink. Convenience is a matter of an absolute need to do something else.
 
Heatspreaders are not all mounted the same. My Opty 165 has one core that's 8c hotter than the other. I am pretty sure it's due to the heatspreader mount. Most of the reports I have seen of removing the heatspreaders results in temps within a couple degrees of each other.

I would suspect the heatspreader mount before any of the other stuff you mention, especially given the amount of care you have taken in your previous HSF/TIM mounts.
 
Then, under those circumstances, I think you imply that it is not correctable even if one were to lap the heatspreader?

That adds a likely candidate for my "assignable causes."

I'm going to remove the heatpipe-cooler today and inspect the TIM, and check the temperatures again.

I'll be posting some temperatures for my "2xORTHOS certification-run," due for termination in a couple hours for "12 hours stable."

Thanks for your input.
 
Back
Top